Flame-resistant polycarbonate blends

ABSTRACT

A thermoplastic molding composition suitable for producing article having excellent flame proofing and improved stress cracking resistance is disclosed. The composition contains an aromatic polycarbonate and/or polyester carbonate, a toughening agent, an optional thermoplastic (co)polymer and a combination of phosphorus compounds.

FIELD OF THE INVENTION

[0001] The present invention relates to toughened polycarbonate blendsthat incorporate a combination of organic phosphorus compounds andinorganic phosphorus/oxygen compounds or phosphorus/sulfur compoundsthat have an excellent flame proofing and improved stress crackingbehaviour (towards media such as solvents or greases).

BACKGROUND OF THE INVENTION

[0002] EP-A 0 640 655 describes moulding compositions composed ofaromatic polycarbonate, styrene-containing copolymers and graft polymersthat can be rendered flame-resistant with monomeric and/or oligomericorganic phosphorus compounds.

[0003] EP-A 0 363 608 describes flame-resistant polymer blends composedof aromatic polycarbonate, styrene-containing copolymer or graftcopolymer and oligomeric organic phosphates as flame retardants.

[0004] U.S. Pat. No. 5,061,745 describes polymer blends composed ofaromatic polycarbonate, ABS graft polymer and/or styrene-containingcopolymer and organic monophosphates as flame retardants.

[0005] A combination of organic phosphorus compounds and inorganicphosphorus/oxygen compounds or phosphorus/sulfur compounds is notdescribed therein. Common to all the applications cited is that, toachieve an excellent flame-proofing with very short burning times, verylarge amounts of phosphates have to be used and these have an adverseeffect on the stress cracking behaviour of the respective mouldingcompositions.

[0006] The demand for a property combination comprising outstandingflame resistance and very good stress cracking behaviour complies, inparticular, with the demand for increasingly thinner moulded-part wallthicknesses.

DETAILED DESCRIPTION OF THE INVENTION

[0007] The object of the present invention is to provide polycarbonatecompositions having an improved flame resistance and improved stresscracking behaviour in contact with media such as, for example, greases,oils or solvents. This spectrum of properties is demanded, inparticular, in applications in the field of data technology, such as,for instance, for housings of monitors, printers, copiers, notebooksetc.

[0008] It has now been found that polycarbonate compositions thatcontain a combination of organic phosphorus compounds and inorganicphosphorus/oxygen compounds as flame retardants have the desiredproperties.

[0009] The invention therefore relates to thermoplastic moldingcompositions containing

[0010] A) aromatic polycarbonate and/or polyester carbonate,

[0011] B) impact modifier,

[0012] C) optionally, thermoplastic homopolymer and/or copolymer,

[0013] D) a combination of

[0014] D.1 phosphorus compound and

[0015] D.2 phosphorus/oxygen compound different from D.1 orphosphorus/sulfur compound or the reaction product of D.1 and D.2.

[0016] Component D is preferably present in an amount of 0.1 to 30 partsby weight (relative to the entire composition). Preferably, componentD.2 contains a phosphorous/oxygen compound.

[0017] The invention preferably relates to blends containing

[0018] A) 40 to 99, preferably 60 to 98.5 parts by weight of aromaticpolycarbonate and/or polyester carbonate,

[0019] B) 0.5 to 60, preferably 1 to 40, in particular 2 to 25 parts byweight of a graft polymer of

[0020] B.1) 5 to 95, preferably 30 to 80 wt % of one or more vinylmonomers on

[0021] B.2) 95 to 5, preferably 20 to 70 wt % of one or more graft baseshaving a glass-transition temperature of<10° C., preferably<0° C.,particularly preferably<−20° C.,

[0022] C) 0 to 45, preferably 0 to 30, particularly preferably 2 to 25parts by weight of at least one thermoplastic polymer selected from thegroup consisting of vinyl (co)polymers and polyalkylene terephthalates,

[0023] D) 0.1 to 30 parts by weight, preferably 1 to 25 parts by weight,particularly preferably 2 to 20 parts by weight of a combination of

[0024] D.1) organic phosphorus compound and

[0025] D.2) a phosphorus/oxygen compound or phosphorus/sulfur compoundand also

[0026] E) 0 to 5, preferably 0.1 to 3, particularly preferably 0.1 to 1part by weight, in particular 0.1 to 0.5 parts by weight of fluorinatedpolyolefin,

[0027] wherein the sum of the parts by weight of the components A-E is100.

[0028] Component A

[0029] According to the invention, suitable aromatic polycarbonatesand/or aromatic polyester carbonates in accordance with component A areknown in the literature and can be prepared by methods known in theliterature (for the preparation of aromatic carbonates, see, forexample, Schnell, “Chemistry and Physics of Polycarbonates”,Interscience Publishers, 1964 and also DE-A 1 495 626, DE-A 2 232 877,DE-A 2 703 376, DE-A 2 714 544, DE-A 3 000 610, DE-A 3 832 396; for thepreparation of aromatic polyester carbonates see, for example, DE-A 3077 934).

[0030] Aromatic polycarbonates are prepared, for example, by reactingdiphenols with carbonyl halides, preferably phosgene, and/or witharomatic dicarboxylic dihalides, preferably benzenedicarboxylicdihalides, by the phase boundary surface method, optionally using chainterminators, for example monophenols, and optionally using trifunctionalor more than trifunctional branching agents, for example triphenols ortetraphenols.

[0031] Diphenols for preparing the aromatic polycarbonates and/oraromatic polyester carbonates are preferably those of the formula (I)

[0032] where

[0033] A is a single bond, C₁-C₅-alkylene, C₂-C₅-alkylidene,C₅-C₆-cycloalkylidene, —O—, —SO—, —CO—, —S—, —SO₂—, C₆-C₁₂-arylene ontowhich further aromatic rings, optionally containing heteroatoms may becondensed, or a radical of the formula (IIa) or (IIb)

[0034] where

[0035] B is, in each case, C₁-C₁₂-alkyl, preferably methyl, halogen,preferably chlorine and/or bromine,

[0036] x is, in each case, independently of one another 0,1or 2,

[0037] p is 1 or 0 and

[0038] R⁷ and R⁸ are, individually selectable for every X¹ andindependently of one another, hydrogen or C₁-C₆-alkyl, preferablyhydrogen, methyl or ethyl,

[0039] X¹ is carbon and

[0040] m is an integer from 4 to 7, preferably 4 or 5, with the provisothat, at least at one atom X¹, R⁷ and R⁸ are simultaneously alkyl.

[0041] Preferred diphenols are hydroquinone, resorcinol,dihydroxydiphenols, bis(hydroxyphenyl)-C₁-C₅-alkanes,bis(hydroxyphenyl)-C₅-C₆-cycloalkanes, bis(hydroxyphenyl) ethers,bis(hydroxyphenyl) sulfoxides, bis(hydroxyphenyl) ketones,bis(hydroxyphenyl) sulfones andα,α-bis(hydroxyphenyl)diisopropylbenzenes and also theirnucleus-brominated and/or nucleus-chlorinated derivatives.

[0042] Particularly preferred diphenols are 4,4′-dihydroxydiphenyl,bisphenol A, 2,4-bis(4-hydroxyphenyl)-2-methylbutane,1,1-bis(4-hydroxphenyl)-cyclohexane,1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxydiphenysulfone and alsotheir di- and tetrabrominated or chlorinated derivatives, such as, forexample, 2,2-bis(3-chloro-4-hydroxphenyl)propane,2,2-bis(3,5-dichloro-4-hydroxy-phenyl)propane or2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane.

[0043] Preferred, in particular, is 2,2-bis(4-hydroxyphenyl)propane(bisphenol A).

[0044] Diphenols may be used individually or as any desired mixtures.

[0045] The diphenols are known in the literature or are obtainable bymethods known in the literature.

[0046] Suitable for the preparation of thermoplastic aromaticpolycarbonates are chain terminators, for example, phenol,p-chlorophenol, p-tert-butyl-phenol or 2,4,6-tribromophenol and alsolong-chain alkylphenols, such as 4-(1,3-tetramethylbutyl)phenol inaccordance with DE-A 2 842 005 or monoalkylphenols or dialkylphenolshaving in total 8 to 20 carbon atoms in the alkyl substituents, such as3,5-di-tert-butylphenol, p-isooctylphenol, p-tert-octylphenol,p-dodecylphenol and 2-(3,5-dimethylheptyl)phenol and4-(3,5-dimethylheptyl)phenol. The amount of chain terminators used is ingeneral between 0.5 mol % and 10 mol %, relative to the molar sum of thediphenols used in each case.

[0047] The thermoplastic aromatic polycarbonates have meanweight-average molecular weights (M_(w) as measured, for example, byultra-centrifuging or light scattering) of 10,000 to 200,000, preferably20,000 to 80,000.

[0048] The thermoplastic aromatic polycarbonates can be branched in aknown manner and, specifically, preferably by the incorporation of 0.05to 2.0 mol %, relative to the sum of the diphenols used, oftrifunctional or more than trifunctional compounds, for example thosecontaining three phenolic groups and over.

[0049] Both homopolycarbonates and copolycarbonates are suitable. Toprepare copolycarbonates according to the invention in accordance withcomponent A, 1 to 25 wt %, preferably 2.5 to 25 wt % (relative to thetotal amount of diphenols used) of polydiorganosiloxanes containinghydroxyaryloxy terminal groups may also be used. These are known (see,for example, U.S. Pat. No. 3 419 634) or can be prepared by methodsknown in the literature. The preparation ofpolydiorganosiloxane-containing copolycarbonates is described, forexample, in DE-A 3 334 782.

[0050] In addition to the bisphenol A homopolycarbonates, preferredpolycarbonates are the copolycarbonates of bisphenol A containing up to15 mol %, relative to the molar sum of diphenols, of other diphenolsnamed as preferred or particularly preferred, in particular2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane.

[0051] Aromatic dicarboxylic dihalides for preparing aromatic polyestercarbonates are preferably the diacid dichlorides of isophthalic acid,terephthalic acid, diphenyl ether 4,4′-dicarboxylic acid and ofnaphthalene-2,6-dicarboxylic acid.

[0052] Particularly preferred are mixtures of the diacid dichlorides ofisophthalic acid and of terephthalic acid in a ratio of between 1:20 and20:1.

[0053] A carbonyl halide, preferably phosgene, is concomitantly used asa bifunctional acid derivative in addition in the preparation ofpolyester carbonates.

[0054] In addition to the monophenols already mentioned, theirchloroformates and also the acid chlorides of aromatic monocarboxylicacids, which may optionally be substituted by C₁-C₂₂-alkyl groups or byhalogen atoms, and also aliphatic C₂-C₂₂-monocarboxylic chlorides aresuitable as chain terminators for the preparation of aromatic polyestercarbonates.

[0055] The amount of chain terminators is, in each case, 0.1 to 10 mol%, relative in the case of the phenolic chain terminators to moles ofdiphenols and in the case of monocarboxylic chloride chain terminatorsto moles of dicarboxylic dichlorides.

[0056] The aromatic polyester carbonates may also incorporate aromatichydroxycarboxylic acid.

[0057] The aromatic polyester carbonates may be linear or branched in aknown manner (in this connection, see also DE-A 2 940 024 and DE-A 3 007934).

[0058] As branching agents, use may be made, for example, ofthree-functional or multifunctional carboxylic chlorides, such astrimesic trichloride, cyanuric trichloride,3,3′,4,4′-benzophenonetetracarboxylic-tetrachloride,1,4,5,8-napthalinetetracarboxylictetrachloride orpyromellitictetrachloride, in amounts of 0.01 to 1.0 mol % (relative tothe dicarboxylicdichloride used), or three-functional or multifunctionalphenols, such as phloroglucinol, 4,6-dimethyl-2,4,6-tri(4-hydroxyphenyl)heptene-2,4,4-dimethyl-2,4-6-tri(4-hydroxyphenyl)heptane,1,3,5-tri(4-hydroxy-phenyl)benzene, 1,1,1-tri(4-hydroxyphenyl)ethane,tri(4-hydroxy-phenyl)phenylmethane,2,2-bis[4,4-bis(4-hydroxy-phenyl)-cyclohexyl]propane,2,4-bis(4-hydroxyphenyl-isopropyl)phenol, tetra(4-hydroxyphenyl)methane,2,6-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol,2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)propane,tetra(4-[4-hydroxyphenylisopropyl]phenoxy) methane,1,4-bis[(4,4′-dihydorxytriphenyl) methyl]benzene, in amounts of 0.01 to1.0 mol %, relative to the diphenols used. Phenolic branching agents maybe introduced with the diphenols, while acid chloride branching agentsmay be fed in together with the acid dichlorides.

[0059] In the thermoplastic aromatic polyester carbonates, theproportion of carbonate structural units may be varied as desired.Preferably, the proportion of carbonate groups is up to 100 mol %, inparticular up to 80 mol %, particularly preferably up to 50 mol %,relative to the sum of ester groups and carbonate groups. Both the estercomponent and the carbonate component of the aromatic polyestercarbonates may be present in the form of blocks or randomly distributedin the polycondensate.

[0060] The relative solution viscosity (η_(rel)) of the aromaticpolycarbonates and polyester carbonates is in the range from 1.18 to1.4, preferably 1.22 to 1.3 (measured on solutions of 0.5 polycarbonateor polyester carbonate in 100 ml of methylene chloride solution at 25°C.).

[0061] The thermoplastic, aromatic polycarbonates and polyestercarbonates can be used alone or in any desired mixture with one another.

[0062] Component B

[0063] The component B comprises one or more graft polymers of

[0064] B.1 5 to 95, preferably 30 to 80 wt % of at least one vinylmonomer on

[0065] B.2 95 to 5, preferably 70 to 20 wt % of one or more graft baseshaving glass-transition temperatures of<10° C., preferably<0° C.,particularly preferably<−20° C.

[0066] The graft base B.2 has in general a mean particle size (d₅₀value) of 0.05 to 5 μm, preferably 0.10 to 0.5 μm, particularlypreferably 0.20 to 0.40 μm.

[0067] B.1 is preferably a mixture of

[0068] B.1.1 50 to 99 parts by weight of vinyl aromatics and/ornucleus-substituted vinyl aromatics (such as, for example, styrene,α-methylstyrene, p-methylstyrene, p-chlorostyrene) and/or C₁-C₄-alkylmethacrylates (such as, for example, methyl methacrylate, ethylmethacrylate) and

[0069] B.1.2 1 to 50 parts by weight of vinyl cyanides (unsaturatednitriles, such as acrylonitrile and methacrylonitrile) and/orC₁-C₈-alkyl (meth)acrylates (such as, for example, methyl methacrylate,n-butyl acrylate, tert-butyl acrylate) and/or derivatives (such asanhydrides or imides) of unsaturated carboxylic acids (for example,maleic anhydride and N-phenylmaleimide).

[0070] Preferred monomers B.1.1 are at least one of the monomersstyrene, α-methylstyrene and methyl methacrylate and, preferably,monomers B.1.2 are at least one of the monomers acrylonitrile, maleicanhydride and methyl methacrylate.

[0071] Particularly preferred monomers are B.1.1 styrene and B.1.2acrylonitrile.

[0072] Suitable graft bases B2 for the graft polymers B are, forexample, diene rubbers, EP(D)M rubbers, that is to say those based onethylene/propylene or ethylene/propylene/diene; furthermore acrylaterubbers, polyurethane rubbers, silicone rubbers, chloroprene rubbers andethylene/vinyl acetate rubbers.

[0073] Preferred graft bases B.2 are diene rubbers (for example, basedon butadiene, isoprene, etc.) or mixtures of diene rubbers or copolymersof diene rubbers or their mixtures with further copolymerizable monomers(for example, in accordance with B.1.1 and B.1.2), with the proviso thatthe glass-transition temperature of the component B.2 is<10° C.,preferably <0° C., particularly preferably<−10° C.

[0074] Particularly preferred is pure polybutadiene rubber.

[0075] Particularly preferred polymers B are, for example, ABS polymers(emulsion, bulk and suspension ABS), such as are described, for example,in DE-A 2 035 390 (=U.S. Pat. No. 3 644 574) or in DE-A 2 248 242 (=GB-A1 409 275) or in the Ullmann Encyclopaedia of Industrial Chemistry, Vol.19 (1980), pages 280 ff. The gel component of the graft base B.2 is atleast 30 wt %, preferably at least 40 wt % (measured in toluene).

[0076] The graft copolymers B may be prepared by free-radicalpolymerization, for example by emulsion, suspension, solution or bulkpolymerization, preferably by emulsion polymerization.

[0077] Particularly suitable graft rubbers are also ABS polymers thatare produced by redox initiation using an initiator system composed oforganic hydroperoxide and ascorbic acid in accordance with U.S. Pat. No.4 937 285.

[0078] Since the graft monomers are known not necessarily to be graftedcompletely onto the graft base during the graft reaction, graft polymersB are understood as meaning, according to the invention, only thoseproducts that are obtained by graft polymerization of the graft monomersin the presence of the graft base.

[0079] (See the note above relative to the inconsistency) Suitableacrylate rubbers according to B.2 of the polymers B are preferablypolymers of alkyl acrylates, optionally with up to 40 wt %, relative tothe weight of B, of other ethylenically unsaturated monomers that can bepolymerized onto B.2. The preferred polymerizable acrylates includeC₁-C₈-alkylesters, for example methyl, ethyl, butyl, n-octyl and2-ethylhexyl ester; haloalkyl esters, preferably halo-C₁-C₈-alkylesters, such as chloroethyl acrylate, and also mixtures of saidmonomers.

[0080] For the purpose of crosslinking, monomers containing more thanone polymerizable double bond may be copolymerized. Preferred examplesof crosslinking monomers are esters of unsaturated monocarboxylic acidscontaining 3 to 8 carbon atoms and unsaturated monohydric alcoholscontaining 3 to 12 carbon atoms, or saturated polyols containing 2 to 4OH groups and 2 to 20 carbon atoms, such as, for example, ethyleneglycol dimethacrylate, allyl methacrylate; polyunsaturated heterocycliccompounds, such as, for example, trivinyl cyanurate and triallylcyanurate; polyfunctional vinyl compounds, such as di- andtrivinylbenzenes; and also triallyl phosphate and diallyl phthalate.

[0081] Preferred crosslinking monomers are allyl methacrylate, ethyleneglycol dimethacrylate, diallyl phthalate and heterocyclic compoundscontaining at least three ethylenically unsaturated groups.

[0082] Particularly preferred crosslinking monomers are the cyclicmonomers trialkyl cyanurate, triallyl isocyanurate,triacryloylhexahydro-s-triazine and triallylbenzenes. The amount of thecrosslinked monomers is preferably 0.02 to 5, in particular 0.05 to 2 wt%, relative to the graft base B.2.

[0083] In the case of cyclic crosslinking monomers containing less thanthree ethylenically unsaturated groups, it is advantageous to restrictthe amount to below 1 wt % of the graft base B.2.

[0084] Preferred “other” polymerizable, ethylenically unsaturatedmonomers that may optionally serve to prepare graft base B.2 in additionto acrylates are, for example, acrylonitrile, styrene, α-methylstyrene,acrylamides, vinyl-C₁-C₆-alkyl ethers, methylmethacrylate and butadiene.Preferred acrylate rubbers as graft base B.2 are emulsion polymershaving a gel content of at least 60 wt %.

[0085] Further suitable graft bases in accordance with B.2 are siliconerubbers containing active graft positions, such as those described inDE-A 3 704 657, DE-A 3 704 655, DE-A 3 631 540 and DE-A 3 631 539.

[0086] The gel content of the graft base B.2 is determined at 25° C. ina suitable solvent (M. Hoffmann, H. Krömer, R. Kuhn, Polymeranalytik Iund II (Polymer analysis I and II), Georg Thieme-Verlag, Stuttgart,1977).

[0087] The mean particle size d₅₀ is the diameter above and below which50 wt % of the particles are in each case. It can be determined by meansof ultracentrifuging measurements (W. Scholtan, H. Lange, Kolloid, Z.and Z. Polymere, 250 (1972), 782-1796).

[0088] Component C

[0089] The component C comprises one or more thermoplastic vinyl(co)polymers C.1 and/or polyalkylene terephthalates C.2.

[0090] Suitable as vinyl (co)polymers C.1 are polymers of at least onemonomer from the group comprising the vinyl aromatics, vinyl cyanides(unsaturated nitriles), C₁-C₈-alkyl (meth)acrylates, unsaturatedcarboxylic acids and also derivatives (such as anhydrides and imides) ofunsaturated carboxylic acids. Suitable, in particular, are (co)polymersof

[0091] C.1.1 50 to 99, preferably 60 to 80 parts by weight of vinylaromatics and/or nucleus-substituted vinyl aromatics (such as, forexample, styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene)and/or C₁-C₈-alkyl methacrylates (such as, for example, methylmethacrylate, ethyl methacrylate, and

[0092] C.1.2 1 to 50, preferably 20 to 40 parts by weight of vinylcyanides (unsaturated nitriles) such as acrylonitrile andmethacrylonitrile and/or C₁-C₈-alkyl (meth)acrylates (such as, forexample, methyl methacrylate, n-butyl acrylate, tert-butyl acrylate)and/or unsaturated carboxylic acids such as maleic acid) and/orderivatives (such as anhydrides and imides) of unsaturated carboxylicacids (for example, maleic anhydride and N-phenylmaleimide).

[0093] (Co)polymers C.1 are resinous, thermoplastic and rubber-free.Particularly preferred is the copolymer of C.1.1 styrene and C.1.2acrylonitrile.

[0094] The (co)polymers in accordance with C.1 are known and can beprepared by free-radical polymerization, in particular by emulsion,suspension, solution or bulk polymerization. The (co)polymers preferablyhave molecular weights {overscore (M)}_(w) (average weight determined bylight scattering or sedimentation) of between 15,000 and 200,000.

[0095] The polyalkylene terephthalates of the component C.2 are reactionproducts of aromatic dicarboxylic acid or their reactive derivatives,such as dimethyl esters or anhydrides, and aliphatic, cycloaliphatic oraraliphatic diols and also mixtures of said reaction products.

[0096] Preferred polyalkylene terephthalates contain at least 80 wt %,preferably at least 90 wt %, relative to the dicarboxylic acidcomponent, of terephthalic acid radicals and at least 80 wt %,preferably at least 90 mol %, relative to the diol component, ofethylene glycol and/or butane diol 1,4-radicals.

[0097] The preferred polyalkylene terephthalates may contain, inaddition to terephthalate radicals, up to 20 mol %, preferably up to 10mol %, of radicals of other aromatic or cycloaromatic dicarboxylic acidscontaining 8 to 14 carbon atoms or aliphatic dicarboxylic acidscontaining 4 to 12 carbon atoms, such as, for example, phthalic acid,isophthalic acid, naphthalene-2,6-dicarboxylic acid,4,4′-diphenyldicarboxylic acid, succinic acid, adipic acid, sebacicacid, azelaic acid and cyclohexanediacetic acid radicals.

[0098] The preferred polyalkylene terephthalates may contain, inaddition to ethylene glycol or butanediol 1,4-radicals, up to 20 mol %,preferably up to 10 mol % of other aliphatic diols containing 3 to 12carbon atoms or cycloaliphatic diols containing 6 to 21 carbon atoms,for example radicals of 1,3-propanediol, 2-ethyl-1,3-propanediol,neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol,1,4-cyclohexanedimethanol, 3-ethyl-2,4-pentanediol,2-methyl-2,4-pentanediol, 2,2,4-trimethyl-1,3-pentanediol,2-ethyl-1,3-hexanediol, 2,2-diethyl-1,3-propanediol, 2,5-hexanediol,1,4-di(β-hydroxyethoxy) benzene, 2,2-bis(4-hydroxycyclohexyl)propane,2,4-dihydroxy-1,1,3,3-tetramethyl cyclobutane,2,2-bis(4-α-hydroxy-phenyl)propane and2,2-bis(4-hydroxypropoxyphenyl)propane (DE-OS 2 407 674, 2 407 776, 2715 932).

[0099] The polyalkylene terephthalates may be branched by incorporatingrelatively small amounts of trihydric or tetrahydric alcohols ortribasic or tetrabasic carboxylic acids, for example in accordance withDE-A 1 900 270 and U.S. Pat. No. 3,692,744. Examples of preferredbranching agents are trimesic acid, trimellitic acid, trimethylolmethaneand trimethylolpropane and pentaerythritol.

[0100] Particularly preferred are polyalkylene terephthalates that havebeen prepared solely from terephthalic acid and its reactive derivatives(for example, its dialkylesters) and ethylene glycol and/or1,4-butanediol and blends of said polyalkylene terephthalates.

[0101] Blends of polyalkylene terephthalates contain 1 to 50 wt %,preferably 1 to 30 wt % of polyethylene terephthalate and 50 to 99 wt %,preferably 70 to 99 wt % of polybutylene terephthalate.

[0102] The polyalkylene terephthalates preferably used have, in general,an intrinsic viscosity of 0.4 to 1.5 dl/g, preferably 0.5 to 1.2 dl/g,measured in phenol/o-dichlorobenzene (1:1 parts by weight) at 25° C. inthe Ubbelohde viscometer.

[0103] The polyalkylene terephthalates can be produced by known methods(see, for example, Kunststoff-Handbuch (Plastics Manual), Volume VIII,pages 695 ff., Carl-Hanser-Verlag, Munich, 1973).

[0104] Component D

[0105] D.1 in component D is preferably present in amounts of 50-98wt.-%, particularly preferred in amounts of 70 to 98 wt.% and inparticular in amounts of 75 to 95 wt.% and D.2 preferably in amounts of50 to 2 wt.-%, particularly preferred in amount of 30 to 2 wt.% and inparticular in amounts of 25 to 5 wt.% relative to the weight of D.

[0106] Phosphorous-containing flame retardants in accordance withcomponent D.1 are preferably selected from among the monomeric andoligomeric phosphoric and phosphonic acid esters, phosphonate amines andphosphazenes, it also being possible to use mixtures of severalcomponents selected from one or several of these groups as flameretardants. Other halogen-free phosphorus compounds not speciallymentioned here may be used alone or in any desired combination withother halogen-free phosphorus compounds.

[0107] Preferred monomeric and oligomeric phosphoric acid or phosphonicacid esters are phosphorus compounds of the general formula (III)

[0108] where

[0109] R¹, R², R³ and R⁴ are, independently of one another, in each caseoptionally halogenated C₁- to C₈-alkyl, optionally substituted in eachcase by alkyl, preferably C₁-C₄-alkyl, and/or halogen-substituted,preferably chlorine-substituted or bromine-substituted, C₅- toC₆-cycloalkyl, C₆- to C₂₀-aryl or C₇- to C₁₂-arylkyl,

[0110] n is, independently of one another, 0 or 1,

[0111] q is 0 to 30 and

[0112] X is a mononuclear or polynuclear aromatic radical containing 6to 30 carbon atoms or a linear or branched aliphatic radical containing2 to 30 carbon atoms, which may be OH-substituted and contain up to 8ether bonds.

[0113] Preferably, R¹, R², R³ and R⁴ stand, independently of oneanother, for C₁-C₄-alkyl, phenyl, naphthyl or phenyl-C₁-C₄-alkyl. Thearomatic groups R¹, R², R³ and R⁴ may be substituted in turn by halogenand/or alkyl groups, preferably chlorine, bromine and/or C₁-C₄-alkyl.Particularly preferable aryl radicals are cresyl, phenyl, xyleneyl,propylphenyl or butylphenyl and also the corresponding brominated andchlorinated derivatives thereof.

[0114] X in formula (III) is preferably a mononuclear or polynucleararomatic radical containing 6 to 30 carbon atoms. It is preferablyderived from the diphenols of formula (I).

[0115] n in formula (III) may be, independently of one another, 0 or 1,but preferably n is equal to 1.

[0116] q stands for values from 0 to 30. If blends of various componentsof formula (III) are used, blends can be used that preferably havenumber-average q-values of 0.3 to 20, particularly preferably 0.5 to 10,in particular 0.5 to 6.

[0117] X stands, in particular for

[0118]  or their chlorinated or brominated derivatives and, inparticular, X is derived from resorcinol, hydroquinone, bisphenol A ordiphenylphenol. Particularly preferably, X is derived from bisphenol A.

[0119] The use of oligomeric phosphoric acid esters of formula (III)that are derived from bisphenol A is particularly advantageous since thecompositions incorporating said phosphorus compound have a particularlyhigh stress crack resistance and hydrolysis resistance and also aparticularly low tendency to encrustation during the injection-mouldingprocessing. Furthermore, a particularly high heat distortion resistancecan be achieved with said flame retardants.

[0120] Monophosphates (q=0), oligophosphates (q=1-30) or mixtures ofmonophosphates and oligophosphates may be used as component D.1 inaccordance with the invention.

[0121] Monophosphorus compounds of formula III are, in particular,tributyl phosphate, tris(2-chloroethyl) phosphate,tris(2,3-dibromopropyl) phosphate, triphenyl phosphate, tricresylphosphate, diphenylcresyl phosphate, diphenyloctyl phosphate,diphenyl-2-ethylcresyl phosphate, tri(isopropylphenyl) phosphate,halogen-substituted arylphosphates, dimethyl methyl phosphonate,diphenyl methylphosphenate, diethyl phenylphosphonate,triphenylphosphene oxide or tricresylphosphene oxide.

[0122] The phosphorus compounds in accordance with component D.1 offormula (III) are known (cf. for example, EP-A 363 608, EP-A 640 655) orcan be prepared by known methods in an analogous way (for example,Ullmanns Encyclopaedia of Industrial Chemistry, Vol. 18, pages 301 ff.,1979; Houben-Weyl, Methoden der organischen Chemie (Methods of OrganicChemistry), Vol. 12/1, page 43; Beilstein Vol. 6, page 177).

[0123] The mean q-values may be determined by determining thecomposition of the phosphate blend (molecular weight distribution) bymeans of suitable methods (gas chromatography (GC) High Pressure LiquidChromatography (HPLC), Gel permeation chromatography (GPC)) andcalculating the mean values of q therefrom.

[0124] Phosphonate amines are preferably compounds of formula (IV)

A_(3−y)—NB¹ _(y)  (IV)

[0125] in which

[0126] A stands for a radical of formula (Va)

[0127] R¹¹ and R¹² stand, independently of one another, forunsubstituted or substituted C₁-C₁₀-alkyl or for unsubstituted orsubstituted C₆-C₁₀-aryl,

[0128] R¹³ and R¹⁴ stand, independently of one another, forunsubstituted or substituted C₁-C₁₀-alkyl or unsubstituted orsubstituted C₆-C₁₀-aryl or

[0129] R¹³ and R¹⁴ may together form unsubstituted or substitutedheterocyclic ring of 3 to 10 carbon atoms

[0130] y is the numerical values 0, 1 or 2 and

[0131] B¹ stands independently for hydrogen, optionally halogenatedC₂-C₈-alkyl, unsubstituted or substituted C₆-C₁₀-aryl.

[0132] B¹ preferably stands independently for hydrogen, for ethyl,n-propyl or isopropyl, which may be substituted by halogen,unsubstituted or C₆-C₁₀-aryl, in particular phenyl or naphthyl,substituted by C₁-C₄-alkyl and/or halogen.

[0133] Alkyl in R¹¹, R¹², R¹³ and R¹⁴ stands independently preferablyfor methyl, ethyl, n-propyl, isopropyl, n-, iso-, sec- or tert-butyl,pentyl or hexyl.

[0134] Substituted alkyl in R¹¹, R¹², R¹³ and R¹⁴ stands independentlypreferably for halogen-substituted C₁-C₁₀ alkyl, in particular for amonosubstituted or disubstituted methyl, ethyl, n-propyl, isopropyl, n-,iso-, sec- or tert-butyl, pentyl or hexyl.

[0135] C₆-C₁₀-aryl in R¹¹, R¹², R¹³ and R¹⁴ stands independentlypreferably for phenyl, naphthyl or binaphthyl, in particular o-phenyl,o-naphthyl, o-binaphthyl, which may be halogen-substituted (in generalmono-, di- or tri-substituted).

[0136] R¹³ and R¹⁴ may form a ring structure together with the oxygenatoms to which they are directly bound and the phosphorus atom.

[0137] By way of example and preferably, mention is made of:5,5,5′,5′,5″,5″-hexamethyltris(1,3,2-dioxaphosphorinanemethane)amino-2,2′,2″-trioxide of formula (Va-1)

[0138] (Experimental product XPM 1000 produced by Solutia Inc., StLouis, USA), 1,3,2-dioxaphosphorinane-2-methaneamine,N-butyl-N-[(5,5-dimethyl-1,3,2-dioxa-2-phosphorinanyl)methyl]-5,5-dimethylP,2-dioxides, 1,3,2-dioxaphosphorinane-2-methaneamine,N-[(5,5-dimethyl-1,3,2-dioxa-2-phosphorinanyl)methyl]-5,5-dimethyl-N-phenyl P,2-dioxide,1,3,2-dioxaphosphorinane-2-methaneamine, N,N-dibutyl-5,5-dimethyl2-oxide, 1,3,2-dioxaphosphorinane-2-methanimine,N-[(5,5-dimethyl-1,3,2-dioxa-2-phosphorinanyl)methyl]-N-ethyl-5,5-dimethyl P,2-dioxide,1,3,2-dioxaphosphorinane-2-methaneamine,N-butyl-N-[(5,5-dichloromethyl-1,3,2-dioxa-2-phosphorinanyl)methyl]-5,5-dichloromethyl P,2-dioxide,1,3,2-dioxaphosphorinane-2-methaneamine,N-[(5,5-dichloromethyl-1,3,2-dioxa-2-phosphorinanyl)methyl]-5,5-dichloromethyl-N-phenyl P,2-dioxide;1,3,2-dioxa-2-phosphorinane methaneamine,N,N-di(4-chlorobutyl)-5,5-dimethyl 2-oxide,1,3,2-dioxa-2-phosphorinanemethaneimine,N-[(5,5-dimethyl-1,3,2-dioxa-2-phosphorinanyl)methane]-N-(2-chloroethyl)-5,5-di(chloromethyl) P,2-dioxide.

[0139] Preferred are, furthermore:

[0140] Compounds of formulae (Va-2) or (Va-3)

[0141] where

[0142] R¹¹, R¹², R¹³ and R¹⁴ have the meanings specified above.

[0143] Particularly preferred are compounds of formulae (Va-2) and(Va-1).

[0144] The preparation of the phosphate amines is described, forexample, in U.S. Pat. No. 5,844,028.

[0145] Phosphazenes are compounds of formulae (VIa) and (VIb)

[0146] wherein

[0147] R is in each case identical or different and stands for amino, ineach case optionally halogenated, preferably fluorine-halogenated C₁- toC₈-alkyl, or C₁- to C₈-alkoxy, in each case optionally substituted byalkyl, preferably C₁-C₄-alkyl, and/or halogen-substituted, preferablychlorine- and/or bromine-substituted, C₅-C₆-cycloalkyl, C₆- to C₂₀-aryl,preferably phenyl or naphthyl, C₆- to C₂₀-aryloxy, preferably phenoxy,naphthyloxy or C₇- to C₁₂-aralkyl, preferably phenyl-C₁-C₄-alkyl,

[0148] k stands for 0 or a number from 1 to 15, preferably for a numberfrom 1 to 10.

[0149] By way of example mention may be made of:

[0150] Propoxyphosphazene, phenoxyphosphazene, methylphenoxyphosphazene,aminophosphazene and fluoroalkylphosphazene.

[0151] Preferred is phenoxyphosphazene.

[0152] The phosphazenes may be used alone or as mixtures. The radical Rcan always be identical or 2 or more radicals in formulae (la) and (lb)may be different.

[0153] Phosphazenes and their preparation are described, for example, inEP-A 728 811, DE-A 1 961 668 and WO 97/40092.

[0154] The flame retardants may be used alone or in any desired mixturewith one another or in mixtures with other flame retardants.

[0155] Phosphorus/oxygen compounds and phosphorus/sulfur compounds inaccordance with component D.2 are preferably phosphorus oxides andphosphorus sulfides. Particularly preferred is P₂O₅. Aluminiumphosphates, alkaline-earth phosphates, alkali phosphates or ammoniumphosphates are also suitable.

[0156] The phosphorus-containing flame retardant in accordance withcomponent D.1 and the phosphorus compounds in accordance with componentD.2 may be added in the preparation of the polymer blend separately ormixed as a special formulation. Components D.1 and D.2 can be mixed atroom temperature or at elevated temperature. Preferably, these blendsare prepared at temperatures above 100° C., particularly preferablyabove 200° C. In the context according to the invention, those productsare also to be understood that are obtained at higher temperatures fromcomponent D.1 and component D.2.

[0157] Component E

[0158] The fluorinated polyolefins E have fluorine contents preferablyof 65 to 76, in particular of 70 to 76 wt %, and mean particle diametersd₅₀ of 0.05 to 1000, preferably 0,08 to 20 μm. In general, thefluorinated polyolefins F have a density of 1,2 to 2,3 g/cm³. Preferredfluorinated polyolefins F are polytetrafluoroethylene, polyvinylidinefluoride and tetrafluoroethylene/hexafluoropropylene andethylene-tetrafluoroethylene copolymers. The fluorinated polyolefins areknown (cf. “Vinyl and Related Polymers” by Schildknecht, John Wiley &Sons, Inc., New York, 1962, pages 484-494; “Fluoropolymers” by Wall,Wiley Interscience, John Wiley & Sons, Inc., New York, Volume 13, 1970,pages 623-654; “Modern Plastics Encyclopedia”, 1970-1971, Volume 47,No.10 A, October 1970, McGraw-Hill, Inc., New York, pages 134 and 774;“Modern Plastics Encyclopedia”, 1975-1976, October 1975, Volume 52, No.10 A, McGraw-Hill, Inc., New York, pages 27, 28 and 472, and U.S. Pat.No. 3,671,487, 3,723,373 and 3,838,092).

[0159] They can be prepared by known methods, for example bypolymerizing tetrafluoroethylene in an aqueous medium using a catalystthat forms free radicals, for example, sodium peroxydisulfate, potassiumperoxydisulfate or ammonium peroxydisulfate at pressures of 7 to 71kg/cm² and at temperatures of 0 to 200° C., preferably at temperaturesof 20 to 10° C. (see, for example, U.S. Pat. No. 2 393 967 for furtherdetails). Depending on the form in which it is used, the density ofthese materials may be between 1.2 and 2.3 g/cm³ and the mean particlesize between 0.5 and 1000 μm.

[0160] According to the invention, preferred fluorinated polyolefins Eare tetrafluoroethylene polymers having a mean particle diameter of 0.05to 20 μm, preferably 0.08 to 10 μm, and a density of 1.2 to 1.9 g/cm³,and are preferably used in the form of a coagulated mixture of emulsionsof the tetrafluoroethylene polymers F with emulsions of the graftpolymers B.

[0161] Further preferred formulations according to the invention are thefluorinated polyolefins E:

[0162] E.1) as a coagulated mixture containing at least one of thecomponents A to C, the fluorinated polyolefine E or polyolefin blendbeing mixed as an emulsion with at least one emulsion of the componentsA to C and then coagulated,

[0163] E.2) as a precompound with at least one of the components A to C,the fluorinated polyolefins E being mixed as powders with a powder or agranular material of at least one of the components A to C andcompounded in the melt, in general at temperatures from 208° C. to 330°C. in the standard equipment, such as internal mixers, extruders or twinscrews.

[0164] Preferred formulations for the fluorinated polyolefins E arecoagulated mixtures containing a graft polymer B or a vinyl (co)polymerC. Suitable fluorinated polyolefins E that can be used in powdered formare tetrafluoroethylene polymers having a mean particle diameter of 100to 1000 μm and a density of 2.0 g/cm³ to 2.3 g/cm³.

[0165] To prepare a coagulated mixture of B and F, an aqueous emulsion(latex) of a graft polymer B is first mixed with a finely dividedemulsion of a tetrafluoroethylene polymer F; suitabletetrafluoroethylene polymer emulsions usually have a solids content of30 to 70 wt %, in particular of 50 to 60 wt %, preferably of 30 to 35 wt%.

[0166] The amounts specified in the description of component B mayinclude the proportion of graft polymer for the coagulated blend ofgraft polymer and fluorinated polyolefins.

[0167] In the emulsion mixture, the weight ratio of graft polymer B totetrafluoroethylene polymer F is 95:5 to 60:40. The emulsion blend isthen coagulated in a known manner, for example by spray drying, freezedrying or coagulation by adding inorganic or organic salts, acids, basesor organic water-miscible solvents, such as alcohols and ketones,preferably at temperatures of 20 to 150° C., in particular of 50 to 100°C. If necessary, drying can be carried out at 50 to 200° C., preferably70 to 100° C.

[0168] Suitable tetrafluoroethylene polymer emulsions are commerciallyavailable products and are offered for sale, for example, by DuPont asTeflon® 30 N.

[0169] The molding compositions according to the invention may containat least one of the standard additives, such as lubricants and mouldrelease agents, nucleating agents, antistatic agents, stabilizers andalso dyes and pigments.

[0170] The blends according to the invention containing the components Ato E and, optionally, further known additives, such as stabilizers,dyes, pigments, lubricants and mould release agents, nucleating agentsand also antistatic agents, are prepared by mixing the respectiveconstituents in a known manner and melt-compounding and melt-extrudingthem at temperatures of 200° C. to 300° C. in standard equipment such asinternal mixers, extruders and twin-shaft screws, the component Fpreferably being used in the form of the coagulated mixture alreadymentioned.

[0171] The individual constituents may be mixed in a known manner eitherin steps or simultaneously and, specifically, either at about 20° C.(room temperature) or at higher temperature.

[0172] The invention therefore relates also to a method of preparing themoulding compositions.

[0173] Owing to their excellent flame resistance and stress behaviourand their good mechanical properties, the blends according to theinvention are suitable for producing mouldings of any type, inparticular those having enhanced requirements relating to stresscracking behaviour as, for instance, in the case of contact with oils,greases or organic solvents.

[0174] The blends of the present invention may be used to producemouldings of any type. In particular, mouldings can be produced byinjection-moulding. Examples of producible mouldings are: casing partsof any type, for example for domestic appliances, such as fruitpressers, coffee machines and mixers, for office machines, such asmonitors, printers and copiers, covers for the building sector and partsfor the motor vehicle sector. In addition, they may be used in the fieldof electrical engineering because they have very good electricalproperties.

[0175] Furthermore, the molding compositions according to the inventionmay be used, for example, to produce the following mouldings or mouldedparts:

[0176] Internal finishing parts for rail-borne vehicles, hub caps,casings of electrical appliances containing small transformers, casingsfor information-processing and information-transmitting appliances,casings and lining for medical purposes, massaging appliances andcasings therefor, toy vehicles for children, two-dimensional wallcomponents, casings for safety devices, rear spoilers, thermallyinsulated transportation containers, devices for keeping or casing forsmall animals, moulded parts for sanitary and bathroom fittings, covergratings for ventilation openings, and moulded parts for garden andappliance sheds, and casings for garden appliances.

[0177] Further applications are possible

[0178] as appliances for file technology: telecommunication appliances,such as telephone sets and telefax machines, computers, printers,scanners, plotters, monitors, keyboards, typewriters, dictactingmachines, etc,

[0179] as electrical appliances: mains units, chargers, smalltransformers for computers and entertainment electronics, low-voltagetransformers, etc.,

[0180] as garden appliances: garden furniture, mowing-machine casings,pipes and casings for garden irrigation, garden sheds, leaf collectors,shredders, chaff cutters, spraying appliances, etc.,

[0181] in the furniture field: worktops, furniture laminates, shuttercomponents, office furniture, tables, chairs, armchairs, cupboards,shelves, door components, window components, linen drawers, etc.,

[0182] as sport appliances and toys: toy vehicles, seat surfaces,pedals, sports equipment, bicycles, table-tennis tables, home trainers,golf caddies, snowboards, outside parts of boats, camping products,beach chairs, etc.,

[0183] in the indoor and outdoor building sector: house cladding,profiled strips, pipes, cables, shutter components, letterboxes, lampcasings, roof tiles, slabs, partitions, cable ducts, skirting boards,plug sockets, etc.,

[0184] in the field of motor vehicles/rail-borne vehicles: wall and roofcladdings, seat shells, seats, benches, tables, luggage racks, hub caps,rear spoilers, mudguards, tailgates, engine bonnets, side parts, etc.

[0185] A further type of processing is the production of mouldings bythermoforming from prefabricated slabs or films.

[0186] The present invention therefore relates, furthermore, also to theuse of the moulding compositions according to the invention forproducing mouldings of any type, preferably of the abovementioned types,and also to the mouldings composed of the moulding compositionsaccording to the invention.

EXAMPLES

[0187] Component A

[0188] Linear polycarbonate based on bisphenol A having a relativesolution viscosity of 1.252, measured in CH₂Cl₂ as solvent at 25° C. andat a concentration of 0.5 g/100 ml.

[0189] Component B

[0190] Graft polymer of 40 parts by weight of a copolymer of styrene andacrylonitrile in a ratio of 72:28 to 60 parts by weight of particulate,crosslinked polybutadiene rubber (mean particle diameter d₅₀=0.40 μm),prepared by emulsion polymerization.

[0191] Component C

[0192] Styrene/acrylonitrile copolymer having a styrene/acrylonitrileweight ratio of 72:28 and an inherent viscosity of 0.55 dl/g (measuredin dimethylformamide at 20° C.).

[0193] Component D

[0194] D.1.1 Triphenylphosphate, disflamoll TP® supplied by Bayer AGLeverkusen, Germany.

[0195] D.1.2 m-Phenylene bis(di-phenyl phosphate), Fyrolflex® suppliedby AKZO, Nobel Chemicals GmbH, 52349 Düren, Germany.

[0196] D.2 Commercially available P₂O₅, supplied by Riedel-de Haen,Germany.

[0197] Da) Mixture of Dl.1 and D.2 Preparation: The triphenyl phosphateis melted under nitrogen at 60° C. Then the phosphorus pentoxide isadded. The mixture is stirred vigorously for 10 min, heated to 270° C.and kept at this temperature for 120 minutes. After the reaction, theproduct is cooled, in which process needle-shaped crystals are produced.

[0198] The triphenyl phosphate: P₂O₅ ratio in Da) is 90:10.

[0199] Db) Preparation as for Da), but only 30 min at 270° C. Thetriphenyl phosphate: P₂O₅ ratio in Db) is 75:25. Db) is a viscousliquid.

[0200] Component E

[0201] Tetrafluoroethylene polymer as a coagulated mixture of a SANgraft polymer emulsion in accordance with component B in water and atetrafluoroethylene polymer emulsion in water. The weight ratio of graftpolymer B to tetrafluoroethylene polymer E in the mixture is 90 wt % to10wt %. The tetrafluoroethylene polymer emulsion has a solids content of60wt % and the mean particle diameter is between 0.05 and 0.5 μm. Thegraft polymer emulsion has a solids content of 34 wt % and a mean latexparticle diameter of 0.4 μm.

[0202] Preparation of E

[0203] The emulsion of tetrafluoroethylene polymer (Teflon 30 N suppliedby DuPont) is mixed with the emulsion of graft polymer B and stabilisedwith 1.8 wt %, relative to the polymer solid, of phenolic antioxidants.The mixture is coagulated at 85 to 95° C. with an aqueous solution ofMgSO₄ (Epsom salts) and acetic acid at a pH of 4 to 5, filtered andwashed until practically electrolyte free, then freed of most of thewater by centrifugation and then dried at 100° C. to form a powder. Saidpowder can then be compounded with the further components in theequipment described.

[0204] Preparation and Testing of the Moulding Compositions According tothe Invention

[0205] The components are mixed in a 3 l internal mixer. The mouldingsare produced in a type Arburg 270 E injection-moulding machine at 260°C.

[0206] The Vicat B heat resistance is determined in accordance with DIN53 460 (ISO 306) on rods measuring 80×10×4 mm.

[0207] The stress cracking behaviour (ESC behaviour) is investigated onrods measuring 80×10×4 mm (produced at a processing temperature of 260°C.). A mixture of 60 vol. % of toluene and 40 vol. % of isopropanol isused as test medium. The specimens are pre-stretched by means of acircular-arc template (pre-stretching as a percentage) and stored atroom temperature in the test medium,. The stress cracking behaviour isassessed from the crack formation or rupture as a function of thepre-stretching ε) and the exposure time in the test medium.

[0208] The fire behavior of the samples was measured according toUL-Subj. 94 V on rods measuring 127×12.7×1.6 mm produced on an injectionmoulding machine at 260° C.

[0209] The UL 94 V-O classification comprises the properties, describedbelow, of materials that are tested in accordance with the UL 94 Vinstructions.

[0210] The molding compositions in this class do not contain any samplesthat burn for longer than 10 s whenever they are acted on by theresidual flame; they do not have a total burning time of more than 50 swhen each set of samples is acted upon by a flame for the second time;they do not contain any samples that burn off completely up to theholding clamp fixed to the upper end of the sample; they do not compriseany samples that ignite the cottonwool disposed beneath the sample as aresult of burning drops or particles; they also do not contain anysamples that glow for longer than 30 s after removing the test flame.

[0211] Other UL 94 classifications designate samples that are lessflame-resistant or less self-extinguishing because they give off flamingdrops or particles. These classifications are designated as UL 94 V-1and V-2. “N.B.” means “failed” and is the classification of samples thathave a burn time of≧30 s. TABLE Moulding compositions and theirproperties Components 1 6 [parts by Wt] (Comparison) 2 3 4 5(Comparison) 7 8 A 68.4 68.4 68.4 68.4 68.4 83.0 83.0 83.0 B 6.8 6.8 6.86.8 6.8 4.0 4.0 4.0 C 9.3 9.3 9.3 9.3 9.3 1.1 2.2 2.2 D.1.1 8.1 8.1 8.18.1 8.1 — — — D.1.2 2.7 2.7 2.7 2.7 2.7 6.6 — — D2 — 0.25 0.5 0.75 1.0 —Da 6.6 Db 6.6 E 4.2 4.2 4.2 4.2 4.2 3.6 3.6 3.6 Mould 0.4 0.4 0.4 0.40.4 0.4 0.4 0.4 release agent Properties Vicat B120 97 97 97 97 97 108109 116 (° C.) Total burning 32 25 22 19 11 65 36 60 time UL 94 V 1.6 mm(sec) ESC behaviour Rupture, ε_(χ) 2.0% 2.0% 2.0% 2.0% 2.4% 0.8% 1.0%1.4% in (%) Time (min) 2:24 3:37 5:00 5:00 5:00 5:00 5:00 5:00

[0212] In the experimental series 1 to 5, it becomes clear that, if P₂O₅is used, moulding compositions are obtained that have substantiallyshorter burning times and markedly better stress cracking behaviour(rupture at greater pre-stretching or for longer exposure times). Inexperiments 7 and 8, P₂O₅ and triphenyl phosphate were used at elevatedtemperatures to prepare a special formulation that proves to be a veryeffective flame retardant. The molding compound in experiment 7 has atriphenyl phosphate content reduced by 10% and, nevertheless, has aburning time shortened from 65 to 36 seconds, with advantages in heatresistance and stress cracking behaviour.

[0213] Although the invention has been described in detail in theforegoing for the purpose of illustration, it is to be understood thatsuch detail is solely for that purpose and that variations can be madetherein by those skilled in the art without departing from the spiritand scope of the invention except as it may be limited by the claims.

What is claimed is:
 1. A thermoplastic molding composition comprising A) aromatic polycarbonate and/or polyester carbonate, B) impact modifier C) optionally, thermoplastic homopolymer and/or copolymer, D) a combination of D.1 phosphorus compound and D.2 phosphorus/oxygen compound different from D.1 or phosphorus/sulfur compound or the reaction product of D.1 and D.2.
 2. The composition of claim 1 wherein D is present in an amount of 0.1 to 30 parts by weight.
 3. The composition of claim 1 wherein D.2 is a phosphorus/oxygen compound.
 4. The composition of claim 1, wherein D.1 is at least one monomeric or oligomeric member selected from the group consisting of phosphoric acid ester, phosphonic acid ester, phosphonate amine and phosphazene.
 5. The composition of claim 1 wherein D.1 conforms to the general formula (III)

where R¹, R², R³ and R⁴ independently of one another denote an optionally halogenated C₁- to C₈-alkyl, or an optionally substituted by alkyl, and/or halogen C₅- to C₆-cycloalkyl, C₆- to C₂₀-aryl or C₇- to C₁₂-arylalkyl, n is, independently of one another, 0 or 1, q is 0 to 30 and X is a mononuclear or polynuclear aromatic radical containing 6 to 30 carbon atoms, or a linear or branched aliphatic radical containing 2 to 30 carbon atoms, optionally OH-substituted and contain up to 8 ether bonds.
 6. The composition of claim 5, wherein X in formula (III) stands for

or their chlorinated or brominated derivatives.
 7. The composition of claim 5 wherein component D.1 is at least one member selected from the group consisting of monophosphate, and oligophosphate.
 8. The composition of claim 1 wherein D.1 is at least one member selected from among phosphonate amine conforming to formula (IV) A_(3−y)—NB¹ _(y)  (IV) in which A stands for a radical of formula (Va)

R¹¹ and R¹² stand, independently of one another, for unsubstituted or substituted C₁-C₁₀-alkyl or for unsubstituted or substituted C₆-C₁₀-aryl, R¹³ and R¹⁴ stand, independently of one another, for unsubstituted or substituted C₁-C₁₀-alkyl or unsubstituted or substituted C₆-C₁₀-aryl or R¹³ and R¹⁴ together denote an unsubstituted or substituted heterocyclic ring of 3 to 10 carbon atoms, and y is 0, 1 or 2 and B¹ stands independently for hydrogen, optionally halogenated C₂-C₈-alkyl, unsubstituted or substituted C₆-C₁₀-aryl a phosphazene conforming to formulae (VIa) and (VIb)

wherein R is in each case identical or different and stands for amino, in each case optionally halogenated, C₁- to C₈-alkyl or C₁- to C₈-alkoxy, in each case optionally substituted by alkyl, C₄-alkyl, and/or halogen-substituted C₅- to C₆-cycloalkyl, C₆- to C₂₀-aryl, C₆- to C₂₀-aryloxy, or C₇-C₁₂-aralkyl, k is an integer of 0 to
 15. 9. The composition of claim 1 wherein D.2 is at least one member selected from the group consisting of phosphorus oxide, phosphorus sulfide, aluminum phosphate, alkaline-earth phosphate, alkali phosphate and ammonium phosphate.
 10. The composition of claim 9 wherein phosphorus oxide is phosphorous pentoxide.
 11. The composition of claim 1 further containing an anti-dripping agent.
 12. The composition of claim 1 wherein impact modifier is a graft polymer of B.1 5 to 95 wt % of at least one vinyl monomer on B.2 95 to 5 wt % of one or more graft bases having glass-transition temperatures lower than 10° C.
 13. The composition of claim 12 wherein B.1 contains B.1.1. 50 to 99 parts by weight of at least one member selected from the group consisting of vinyl aromatic, nucleus-substituted vinyl aromatics and C₁-C₄-alkyl methacrylates, and B.1.2 1 to 50 parts by weight of at least one member selected from the group consisting of vinyl cyanide, C₁-C₈-alkyl methacrylate and a derivative of unsaturated carboxylic acid.
 14. The composition of claim 13 wherein B1.1 is at least one member selected from the group consisting of styrene, α-methylstyrene and methyl methacrylate and wherein B.1.2 is at least one member selected from the group consisting of acrylonitrile, maleic anhydride and methyl methacrylate.
 15. The composition of claim 14 wherein B.1.1 is styrene and B.1.2 is acrylonitrile.
 16. The composition of claim 12 wherein the graft base B.2 is at least one member selected from the group consisting of diene rubber, EP(D)M rubber, acrylate rubber, polyurethane rubber, silicon rubber, chloroprene rubber and ethylene/vinyl acetate rubber.
 17. The composition of claim 16, wherein diene rubber is a copolymer of diene.
 18. The composition of claims 1 wherein said C is at least one member selected from the group consisting of thermoplastic vinyl (co)polymer and polyalkylene terephthalate.
 19. The composition of claim 11 wherein the anti-dripping agent is fluorinated polyolefin.
 20. A thermoplastic molding composition comprising A) 40 to 99 parts by weight of aromatic polycarbonate and/or polyester carbonate, B) 0.5 to 60 parts by weight of a graft polymer of B.1) 5 to 95 wt. % relative to the weight of B of one or more vinyl monomers on B.2) 95 to 5 wt. % relative to the weight of B of one or more graft bases having a glass-transition temperature lower than 10° C., C) 0 to 45 parts by weight of at least one thermoplastic polymer selected from the group consisting of vinyl (co)polymer and polyalkylene terephthalate, D) 0.1 to 30 parts by weight of a combination of D.1) organic phosphorus compound and D.2) a phosphorus/oxygen compound or phosphorus/sulfur compound and E) 0 to 5 parts by weight of an anti-dripping agent, wherein the sum of the parts by weight of the components A-E is
 100. 21. A method of using the composition of claim 1 comprising producing molded articles.
 22. A molded article comprising the composition of claim
 1. 